Method and system for use in performing security screening

ABSTRACT

A method and apparatus for screening luggage are provided. X-ray images derived by scanning the luggage with X-rays are received and processed with an automated threat detection (ATD) engine. A determination is then made whether to subject respective ones of the X-ray images to further visual inspection by a human operator at least in part based on results obtained by the ATD engine. In certain cases, visual inspection by a human operator is by-passed and the ATD results are relied upon in order to mark luggage for further inspection or to mark luggage as clear. In another aspect, X-ray images derived by scanning the luggage using two or more X-ray scanning devices are pooled at a centralized location. ATD operations are applied to the X-ray images, which are then provided “on-demand” to a human operator for visual inspection. Results of the visual inspection are entered by the human operator and then conveyed to on-site screening technicians associated with respective X-ray scanning devices.

CROSS-REFERENCE TO RELATED APPLICATIONS

For the purpose of the United States, the present application claims thebenefit of priority under 35 USC §119(e) based on:

U.S. provisional patent application Ser. No. 61/326,503 filed on Apr.21, 2010 by Luc Perron; and

U.S. provisional patent application Ser. No. 61/420,973 filed on Dec. 8,2011 by Luc Perron.

The present application is also a continuation application claiming debenefit of priority under 35 U.S.C. §120 based on U.S. patentapplication Ser. No. 13/642,353 filed on Oct. 19, 2012 which was anational phase entry application under 35 USC 371 of International PCTPatent Application No. PCT/CA2011/000474 filed on Apr. 21, 2011.

The contents of the above-referenced patent documents are incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention relates generally to security systems and, moreparticularly, to a security screening system for assisting screeningoperators in the detection of potential threats in receptacles, inparticular carry-on luggage, and to a method and/or apparatus forimproving the efficiency of security screening processes at securitycheckpoints.

BACKGROUND

Security in airports, train stations, ports, mail sorting facilities,office buildings and other public and/or private venues is becomingincreasingly important, particularly in light of recent violent events.

Typically, checkpoint security-screening systems make use of scanningdevices (such as X-ray scanning devices) that use penetrating radiationto scan individual pieces of luggage (or other objects). Such scanningdevices generally include a conveyor belt on which the pieces of luggage(or other objects) are positioned, either directly or on a support suchas a tray. The conveyor belt displaces the objects positioned thereontowards an inspection area, also referred to as the scanning tunnel,where the objects are subjected to penetrating radiation. The scanningdevices typically generate images (X-ray images in the case of an X-rayscanning device) that convey information related to the contents of thepieces luggage. Each scanning device includes a display device connectedthereto on which images are rendered. A human operator visually inspectsthe images in order to determine whether there could be any potentiallythreatening objects located in the luggage. In conventional systems, arespective human operator is assigned to each scanning device in orderto visually inspect the images that are generated. Typically that sameoperator also controls the movement of the conveyor belt of the scanningdevice. Once a piece of luggage has been screened by visually inspectingthe image(s), the human operator typically identifies the piece ofluggage either as being clear, in which case it can be collected by itsowner, or by marking it for further inspection, in which case the pieceis luggage is forwarded to secondary screening where additional securityscreening is performed (for example a manual inspection or other).

For each piece of luggage screened, there is an inherent delayassociated with the piece of luggage being displaced on the conveyorbelt. It has been observed that, for an average X-ray machine currentlyin use, it take approximately two (2) seconds to scroll an image of apiece of luggage on the display screen of a human operator. During thattime the operator's time is essentially not used to visually inspect theimage. Additional delays are incurred when the human operator needsadditional time to be able to satisfy himself/herself that there are notprohibited objects in the piece of luggage. In such cases, the operatormay temporary stop the conveyor belt and/or have the conveyor beltoperate in reverse so that the piece of luggage is rescanned by thescanning device.

At airports, the above issues are further being compounded by theincrease in the number of individual items that need to be screened atthe security checkpoints. Although security measures, such as taking alaptop out of a bag for screening, restricting the quantity of liquidsand gels allowed in carry-on bags, and removing shoes, are all fairlyreasonable risk mitigation strategies designed to make air travel safer,they resulted in a lot more individual items being scanned than in thepast. More items to scan necessarily requires more time to process. Thedelays associated with the screening of objects at security checkpointscan be significant and contribute to increase the level of frustrationof travellers. In busy airports, it is now not uncommon to recommendthat passengers arrive several hours (often two or three hours) prior tothe scheduled departure time of their flight.

One of the approaches that can assist in countering the effects of thesedelays at security checkpoints is the use of automated threat detection(ATD). Generally ATD work in tandem with the scanning devices.Typically, when ATD functionality is provided, each scanning device isprovided with ATD functionality for processing the images generated bysubjecting pieces of luggage (or other objects) to penetrating radiationin order to identify regions of interests in the images (e.g. regionspotential containing threats). If a region of interest is identified inan image, the image displayed to the human operator on the displayscreen associated with the scanning device is typically annotated by theATD system to direct the attention of the human operator to the regionof interest, for example by highlighting the region of interest in theimage.

Although the use of automated threat detection (ATD) in principle allowsa reduction in the delays associated with an operator examining an imageof individual pieces of luggage, it does not address delays associatedwith the pieces of luggage being displaced on the conveyor belt. Thisapproach also does not counter the effects of the increase in the numberof additional objects that need to be individually screened to satisfynew security regulations.

Another approach used to accounts for the effects of these delays atsecurity checkpoints is to provide multiple scanning devices in order tobe able to process multiple passengers, or crew members, in parallel.While multiple scanning devices in use at the same time is advantageousfrom the perspective of being able to screen a large number ofindividuals relatively quickly, it increases the number of operatorsrequired to man the checkpoints thereby resulting in higher costs forthe airports and/or security agency responsible for staffing thesecheckpoints. With every new security screening requirement, screeningcosts are continuously on the rise despite the best efforts from airportauthorities.

In view of the above, there is a need in the industry for providing animproved security checkpoint screening system that addresses at leastsome of the deficiencies of existing screening systems.

SUMMARY

In accordance with a first broad aspect, the invention provides a methodfor screening pieces of luggage. The method comprises receiving X-rayimages derived by scanning the pieces of luggage with X-rays. The methodalso comprises processing the X-ray images with an automated threatdetection engine and determining whether to subject respective ones ofthe X-ray images to a visual inspection by a human operator at least inpart based on results obtained by the automated threat detection engine.

In a specific implementation, the method also comprises by-passingvisual inspection of at least some of the X-ray images at least in partbased on the results obtained by the automated threat detection engine.

Advantageously, by-passing visual inspection by human operators ofcertain X-ray images reduces the amount of time human operators need tospend screening X-ray images thereby resulting in improvements inefficiency for the screening of pieces of luggage. For example, insteadof systematically dispatching all X-ray images (with or withoutautomated detection results) for visual inspection, the dispatch forvisual inspection can be made in a selective manner. By using resultsobtained by the automated threat detection engine when determiningwhether to submit an X-ray image to a visual inspection by a human, alevel of quality of the security screening can be maintained whileachieving improved efficiency.

In a first non-limiting example, if the automated threat detectionengine determines with a high level of confidence that an X-ray imagecontains a threat, it is likely that the human operator based on avisual inspection of the X-ray image would mark the piece of luggage forfurther inspection. Thus the visual inspection of that image can beskipped (by-passed) and the results obtained by the automated threatdetection engine relied upon without affecting the quality of thescreening process.

In a second non-limiting example, which may be used concurrently with orseparately from the first non-limiting example, if the automated threatdetection engine determines with a high level of confidence that anX-ray image depicts contents that are considered “safe” (the X-ray imageis unlikely to contain a threat), it is likely that the human operatorbased on a visual inspection of the X-ray image would mark the image as“clear”. Thus in this situation the visual inspection of that image canlikely be skipped and the results obtained by the automated threatdetection engine relied upon without affecting the quality of thescreening process.

In accordance with a second broad aspect, the invention provides amethod for screening pieces of luggage. The method comprises receivingX-rays image data derived by scanning the pieces of luggage with X-rays,the X-ray image data conveying images depicting the pieces of luggage.The method also comprises processing the images conveyed by the X-rayimage data to identify candidate images for by-passing visual inspectionat least in part based on results obtained by processing the X-ray imagedata with an automated threat detection engine. The method alsocomprises displaying on a display device at least some images conveyedby the X-ray image data for visual inspection by a human operator andby-passing visual inspection of at least some of the identifiedcandidate images.

In a specific example of implementation, the images displayed for visualinspection convey to the human operator information derived at least inpart based on the results obtained by processing the X-ray image datawith the automated threat detection engine.

In a specific example of implementation, the method comprises assigningthreat level indicators to pieces of luggage associated with thecandidate images at least in part based on the results obtained byprocessing the X-ray image data with the automated threat detectionengine. The method may also comprise assigning threat level indicatorsto pieces of luggage associated with images displayed for visualinspection at least in part based on results of the visual inspection.In a non-limiting example, the threat level indicators convey thatassociated pieces of luggage are either marked for further inspection orare marked as “clear”.

In a specific implementation, the method comprises displayinginformation derived at least in part based on the threat levelindicators to on-site screening technicians located in proximity to thescanned pieces of luggage.

In a non-limiting example of implementation, the assigned threat levelindicators are used to control a displacement of the pieces of luggagethrough a security checkpoint.

In a first exemplary implementation, the control of the displacement ofthe pieces of luggage through a security checkpoint is exercisedmanually by an on-site screening technician. In such implementation, theinformation which is displays to the on-site screening technicianindicates to the on-site screening technician that a piece of luggageshould be directed to either to a luggage collection area (when thethreat level indicator conveys that the piece of luggage is marked asclear) or to an area for dispatch to secondary screening (when thethreat level indicator conveys that the piece of luggage is marked forfurther inspection).

In a second exemplary implementation, the control of the displacement ofthe pieces of luggage through a security checkpoint is exercisedelectronically. In such alternative implementation, the assigned threatlevel indicators is used to control switches in a conveyor systemassociated with the screening stations for directing the pieces ofluggage either to a luggage collection area (when the threat levelindicator conveys that the piece of luggage is marked as clear) or to anarea for dispatch to secondary screening (the threat level indicatorconveys that the piece of luggage is marked for further inspection).

In a specific example of implementation, the results obtained by theautomated threat detection engine include information related todetection of potential threats in the pieces of luggage. In anon-limiting example of implementation, the method comprises identifyingat least one of the images conveyed by the X-ray image data as acandidate image for by-passing visual inspection:

a) when the information derived by the automated threat detection engineconveys detection of a liquid product in an X-ray image. In such asituation, the method may comprise marking for further inspection thepiece of luggage associated with the X-ray image; and/or

b) when the information derived by the automated threat detection engineconveys detection of a threat in an X-ray image. In a non-limitingexample, the detection of the threat in the X-ray image is associatedwith a confidence level exceeding a threshold confidence level that theX-ray image depicts a threat. In such a situation, the method maycomprise marking for further inspection the piece of luggage associatedwith the X-ray image; and/or

c) when the information derived by the automated threat detection engineconveys an indication of safe contents in an X-ray image. In anon-limiting example, the indication of safe contents in the X-ray imageis associated with a confidence level exceeding a threshold confidencelevel. In such a situation, the method may comprise marking as clear thepiece of luggage associated with the X-ray image.

In a specific example of implementation, the X-ray image data is derivedby scanning the pieces of luggage using one or more X-ray scanningdevices. The display device on which are displayed the images for visualinspection is located remotely from the one or more X-ray scanningdevice.

In an alternative example of implementation, the X-ray image data isderived by scanning the pieces of luggage using two or more X-rayscanning devices. In such alternative implementation, the display deviceon which are displayed the images for visual inspection is locatedremotely from the two or more X-ray scanning devices.

In accordance with another broad aspect, the invention provides a methodfor screening pieces of luggage. The method comprises scanning thepieces of luggage with X-rays to generate X-ray image data conveyingimages depicting the pieces of luggage. The method also comprisesprocessing the images conveyed by the X-ray image data to identifycandidate images for by-passing visual inspection at least in part basedon results obtained by processing the X-ray image data with an automatedthreat detection engine. The method also comprises by-passing visualinspection of the identified candidate images and displaying on adisplay device images other than the candidate images for visualinspection by a human operator.

In accordance with another broad aspect, the invention provides a systemfor use in screening pieces of luggage. The system comprises at leastone X-ray scanner for scanning the pieces of luggage with X-rays toderive X-ray image data. The system also comprises a computing deviceincluding an input for receiving the X-ray image data from the X-rayscanner. The computing device is programmed with software for screeningthe pieces of luggage in accordance with the above described method. Thesystem also comprises a display module in communication with thecomputing device for conveying information derived by the computingdevice.

In a specific example of implementation, the system includes at leasttwo X-ray scanners.

In accordance with another broad aspect, the invention provides anapparatus for use in screening pieces of luggage. The apparatuscomprises an input for receiving X-ray image data derived by scanningthe pieces of luggage with X-rays. The apparatus also comprises aprocessing element in communication with the input and programmed forscreening pieces of luggage in accordance with the above describedmethod. The apparatus also comprises an output for releasing dataconveying results obtained by the processing element.

In accordance with another broad aspect, the invention provides acomputer readable storage medium storing a program element for executionby a computing device. The program element, when executed by thecomputing device, causes the execution of a method by the computingdevice of the type described above for screening pieces of luggage.

In accordance with another broad aspect, the invention provides a methodfor screening pieces of luggage. The method comprises receiving at acentralized location X-ray images derived by scanning pieces of luggageusing X-rays, the X-ray images being generated by at least two screeningstations. The method also comprises using an automated threat detectionengine to process the X-ray images by applying automated threatdetection (ATD) operations. The method also comprises, in response to arequest entered by a human operator at a remote screening station incommunication with the centralized location:

i. releasing for display at the remote screening station an X-ray imageon which an ATD operation has been applied, the X-ray image having beengenerated by one of the at least two screening stations;

ii. providing a user interface tool at the remote screening station forallowing the human operator to provide threat assessment informationassociated with the X-ray image being displayed;

iii. in response to receipt of threat assessment information from thehuman operator at the remote screening station, causing the threatassessment information to be conveyed to an on-site screening technicianassociated with the one of the at least two screening stations.

Advantageously, by pooling images generated by at least two (2) at leasttwo screening stations in a centralized location and by making availablefor display these images to a human operator in response to a request, areduction of at least some of the delays associated with the pieces ofluggage being displaced on the conveyor belt can be achieved.

In accordance with a specific example of implementation, the X-ray imageon which an ATD operation has been applied is a first X-ray image onwhich an ATD operation has been applied. In response to receipt ofthreat assessment information from the human operator at the remotescreening station, a second X-ray image on which an ATD operation hasbeen applied is released for display on the remote screening station.The second X-ray image may have been generated by the same screeningstation as the one that generated the first X-ray image of by adifferent screening station.

In a specific implementation, the X-ray image on which the ATD operationhas been applied is conveyed to the on-site screening technicianassociated with the screening station that generated the X-ray imageconcurrently with the threat assessment information provided by thehuman operator at the remote screening station. In a non-limitingimplementation, the threat assessment information provided by the humanoperator conveys a threat level indicator associated with the X-rayimage being displayed. As examples, the threat level indicator mayconvey that the X-ray image being displayed is marked for furtherinspection or that the X-ray image being displayed is marked as clear.

In a non-limiting example of implementation, the threat assessmentinformation provided by the human operator is used to control adisplacement of a piece of luggage at the one of the at least twoscreening stations. In a first exemplary implementation, the control ofthe displacement of the piece of luggage is exercised manually by anon-site screening technician. In such implementation, the threatassessment information indicates to the on-site screening technicianthat a piece of luggage should be directed either to a luggagecollection area (when the threat assessment information conveys that thepiece of luggage is marked as clear) or to an area for dispatch tosecondary screening (when the threat assessment information conveys thatthe piece of luggage is marked for further inspection). Alternatively,in a second exemplary implementation, the control of the displacement ofthe pieces of luggage may be exercised electronically. In suchalternative implementation, the threat assessment information is used tocontrol switches in a conveyor system associated with a screeningstation in order to direct the pieces of luggage either to a luggagecollection area (when the threat assessment information conveys that thepiece of luggage is marked as clear) or to an area for dispatch tosecondary screening (when the threat assessment information conveys thatthe piece of luggage is marked for further inspection).

In a specific example of implementation, the X-ray image on which an ATDoperation has been applied is displayed at the remote screening stationconcurrently with information conveying results obtained by the ATDoperation.

In a specific example of implementation, the method comprises processingX-ray images on which ATD operations have been applied to identifycandidate X-ray images for by-passing visual inspection at the remotescreening station.

In a specific example of implementation, the method comprises, inresponse to identification of a candidate X-ray image for by-pass:

identifying which one of the at least two screening stations generatedthe identified candidate X-ray image;

by-passing visual inspection at the remote screening station of thecandidate X-ray image; and

causing threat assessment information derived based on results obtainedby applying the ATD operation to the candidate X-ray image to beconveyed to an on-site screening technician associated with thescreening station that generated the candidate X-ray image.

In a non-limiting example of implementation, identifying candidate X-rayimages for by-passing visual inspection includes:

a) processing results obtained by applying ATD operations to the X-rayimages; and

b) identifying an X-ray image as a candidate X-ray images for by-passingvisual inspection:

-   -   1. when the threat assessment information derived by applying an        ATD operation to the X-ray image conveys detection of a threat        in the X-ray image; and/or    -   2. when the threat assessment information derived by applying an        ATD operation to the X-ray image conveys an indication of safe        content in the X-ray image.

In accordance with a specific example, the X-ray image on which the ATDoperation had been applied is associated with a piece of luggage beingscreened. The method comprises conveying a picture image of the piece ofluggage being screened to the on-site screening technician associatedwith the screening station that generated the X-ray image concurrentlywith the threat assessment information.

In accordance with a non-limiting example of implementation, pictureimages of the pieces of luggage being screened are derived using astill-shot camera and/or using a video camera and displayed to theon-site screening technician. In a non-limiting implementation, thestill-shot camera and/or video camera may be positioned either at theentrance or the exit of the X-ray devices to provide picture images ofthe pieces of luggage (or objects) under inspection.

Advantageously, providing picture images of the pieces of luggage beingscreened provides additional visual information to the on-site screeningtechnician and facilitates the association of the pieces of luggage andthreat assessment information by the on-site screening technician.

Optionally, a picture image of a piece of luggage may be displayed tothe human operator at the remote screening station concurrently with theX-ray image of the piece of luggage on which an ATD operation has beenapplied. Since the human operator will be unlikely to have the benefitof seeing the physical piece of luggage prior to (or subsequent to)visual inspection, this picture image is intended to provide additionalcontextual information to the human operator at the remote screeningstation, which may influence results of the visual inspection of theX-ray image by the human operator.

In accordance with another broad aspect, the invention provides a systemfor use in screening pieces of luggage. The system comprises at leasttwo X-ray scanners for scanning the pieces of luggage with X-rays toderive X-ray images of the pieces of luggage. The system furthercomprises a computing device including an input for receiving the X-rayimages from the X-ray scanners. The computing device is programmed withsoftware for screening the pieces of luggage in accordance with theabove described method.

In accordance with another broad aspect, the invention provides acomputer readable storage medium storing a program element for executionby a computing device. The program element, when executed by thecomputing device, causes the execution of a method by the computingdevice of the type described above for screening pieces of luggage.

In accordance with another broad aspect, the invention provides a systemfor use in screening pieces of luggage. The system comprises at leasttwo X-ray scanning devices for scanning the pieces of luggage withX-rays to derive X-ray images of the pieces of luggage. The systemfurther comprises at least one automated threat detection engine forprocessing the X-ray images by applying an automated threat detection(ATD) operation. The system further comprises a remote screening stationin communication with the at least two X-ray scanning devices and withthe at least one automated threat detection engine. The remote screeningstation includes a display device for exchanging information with ahuman operator. The remote screening station is responsive to a requestentered at the remote screening station by the human operator for:

releasing for display on the display device an X-ray image on which anATD operation has been applied, the X-ray image having been generated byone of the at least two screening stations;

providing a user interface tool for allowing the human operator toprovide at the remote screening station threat assessment informationassociated with the X-ray image being displayed;

in response to receipt of threat assessment information provided by thehuman operator, causing the threat assessment information provided bythe human operator to be conveyed to an on-site screening technicianassociated with the one of the at least two screening stations.

In accordance with a specific implementation, the system furthercomprises local display devices associated with respective ones of theat least two X-ray scanning devices for conveying threat assessmentinformation to on-site screening technicians associated with the X-rayscanning devices. In accordance with a specific implementation, thethreat assessment information provided by the human operator at theremote screening station is conveyed to the on-site screening technicianassociated with the one of the at least two X-ray scanning devicesthrough an associated one of the local display devices. In non-limitingexamples of implementation, the threat assessment information indicatesto the on-site screening technician whether a piece of luggage is markedas “clear” or marked for further inspection.

In accordance with a specific implementation, the system furthercomprises a processor programmed for determining whether to subjectrespective ones of the X-ray images derived by the at least two X-rayscanning devices to a visual inspection by the human operator at theremote screening station, wherein the determining is made at least inpart based on results obtained by using the automated threat detectionengine.

In accordance with a specific example of implementation, the processoris further programmed to cause at least some of the X-ray images derivedby the at least two X-ray scanning devices to by-pass visual inspectionby the human operator at the remote screening station.

In specific implementations, the X-ray images displayed at the remotescreening station are associated with results obtained by applying anATD operation, so that “on demand” the human operator views both theX-ray image of the piece of luggage as well as the associate ATDresults. In such a system, the latency due to displacing the pieces ofluggage on the conveyor belt at an X-ray scanning devices can be atleast in part accounted for, which results in a more optimized screeningprocess. Depending on the manner in which practical implementations ofthe system are embodied, it is believed that efficiencies in throughputranging between twenty (20%) and thirty (30%) percent over that ofstand-alone X-ray scanning devices could be achieved.

Other aspects and features of the present invention will become apparentto those ordinarily skilled in the art upon review of the followingdescription of specific embodiments of the invention in conjunction withthe accompanying Figures.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of examples of implementation of the presentinvention is provided herein below with reference to the followingdrawings, in which:

FIG. 1 shows a non-limiting example of a security checkpoint screeningsystem in accordance with a specific non-limiting example ofimplementation of the present invention;

FIG. 2 shows a non-limiting example of a scanning device suitable foruse in the security checkpoint screening system of FIG. 1;

FIG. 3 is a diagrammatic representation of an inspection area of thescanning device depicted in FIG. 2;

FIG. 4 is a non-limiting example of a processing module for use inprocessing X-ray images of objects under inspection, such as pieces ofluggage, suitable for use in a security checkpoint screening system ofthe type depicted in FIG. 1;

FIGS. 5-8 show non-limiting examples of processes for processing X-rayimages of objects under inspection, such as pieces of luggage, in asecurity checkpoint screening system of the type depicted in FIG. 1;

FIG. 9 is a block diagram of a computing apparatus suitable forprocessing X-ray images of objects under inspection, such as pieces ofluggage, in a security checkpoint screening system of the type depictedin FIG. 1 in accordance with a specific non-limiting example ofimplementation of the invention;

FIG. 10 is a block diagram of a computing apparatus suitable forprocessing X-ray images of objects under inspection, such as pieces ofluggage, in a security checkpoint screening system of the type depictedin FIG. 1 in accordance with an alternative specific example ofimplementation of the invention;

FIG. 11 shows a functional block diagram of a distributed processingsystem including networked components for implementing a securitycheckpoint screening system in accordance with a specific non-limitingexample of implementation of the invention;

FIG. 12 is a block diagram of a screening station including conveyorsystem for directing pieces of luggage either to a luggage collectionarea or to an area for dispatch to secondary screening in accordancewith a specific non-limiting example of implementation of the invention;

FIG. 13 shows another non-limiting example of a process for processingX-ray images of objects under inspection, such as pieces of luggage, ina security checkpoint screening system of the type depicted in FIG. 1.

In the drawings, embodiments of the invention are illustrated by way ofexample. It is to be expressly understood that the description anddrawings are only for purposes of illustration and as an aid tounderstanding, and are not intended to be a definition of the limits ofthe invention.

DETAILED DESCRIPTION

Specific examples of implementation of the invention will now bedescribed with reference to the Figures. In a specific example, theitems under inspection are pieces of luggage. It however to beappreciated that the concepts presented herein are applicable insituations where the items under inspection are objects other thanpieces of luggage, for example containers of liquid, shoes, lap-tops,purses, wallets, keys or any other type of objects screened at asecurity checkpoint.

Shown in FIG. 1 is an example of a security screening system 10 inaccordance with a non-limiting embodiment of the invention. As shown,the security screening system 10 comprises three (3) security checkpointscreening stations 12, 14 and 16, each comprising a respective scanningdevice 18 that is capable of scanning items (such as pieces of luggageor other objects under inspection) using penetrating radiation (such asX-rays) in order to generate images of the items. The images generatedare generally X-ray images that convey the contents of the scanned item.Examples of items being scanned include, without being limited to,closed suitcases, liquid products comprised of containers holdingliquids, shoes, purses, belts, wallets, phones, cameras and lap-topcomputers.

In the embodiment depicted, the images from each of the securitycheckpoint screening stations 12, 14 and 16 are further processed, forexample by applying automated threat detection (ATD) operations to theimages and/or are displayed on a display device for visual inspection byone or more human operators. The ATD-related functionality may residelocally in the scanning devices 18 of each one of security checkpointscreening stations 12, 14 and 16 or, alternatively, may reside in ascreening module remote from the scanning devices 18, such as in remotescreening module 26 shown in FIG. 1. The further processing (e.g. byapplying ATD operation) alone or in combination with input from the(human) operators determines whether the item under inspection should bemarked as “clear” at the security checkpoint or marked for furtherinspection.

In the embodiment depicted, the images from each of the securitycheckpoint screening stations 12, 14 and 16 are transmitted to acentralized repository 22 to wait for either further processing and/orto be displayed on a display device for visual inspection by one or morehuman operators. In accordance with an alternative embodiment in whichATD-related functionality resides locally in the scanning devices 18,the images generated by the scanning devices 18 are first processed byapplying automated threat detection (ATD) operations to the images atthe scanning devices 18 prior to being transmitted to the centralizedrepository 22 along with the results of obtained by applying the ATDoperations.

The manner in which the images are handled by the security checkpointscreening system 10 will be described in more detail further on in thedescription.

Optionally, each of the security checkpoint screening stations 12, 14and 16 comprises a camera 20 (which could be a video camera orstill-shot camera) that is positioned at the entrance to the scanningdevice 18 to provide a picture image of the item under inspection by thescanning device 18. It should be appreciated that the camera 20 couldalternatively be positioned at the exit of the scanning device 18, or atany location in between the entrance and exit to the scanning device 18,so long as the camera 20 is able to provide a picture image of the itemsunder inspection by the scanning device 18 that provides usefulinformation to a human operator.

As will be described in more detail in the present application, inaccordance with a specific embodiment, a benefit of having a pictureimage of an item under inspection provided by camera 20 is to provideadditional information to on-site screening technicians located at eachof the security checkpoint screening stations. In particular, when theon-site screening technicians are presented with threat assessmentinformation with respect to a piece of luggage, providing a pictureimage of the piece of luggage to the on-site screening technicianfacilitates the matching of the threat assessment information with thepiece of luggage and reduces the likelihood of errors (the wrong pieceof luggage being matched with given threat assessment information). Inaccordance with a specific embodiment, another benefit of having apicture image of an item under inspection provided by camera 20 is toprovide additional contextual information to a human operator, forexample a human operator at remote screening station 32. For example, apicture image of a piece of luggage may be displayed to the humanoperator at the remote screening station 32 concurrently with the X-rayimage of the piece of luggage on which an ATD operation has beenapplied. Since the human operator at the remote screening station 32will be unlikely to have the benefit of seeing the physical piece ofluggage (or other object under inspection) prior to (or subsequent to)visual inspection, this picture image provides additional cues and/orcontextual information to the human operator, which may influenceresults of the visual inspection of the X-ray image.

Although only three (3) security checkpoint screening stations 12, 14and 16 are shown in FIG. 1, it should be appreciated that any number ofsecurity checkpoint screening stations could be included in alternativeembodiments of the security checkpoint screening system 10. A moredetailed description of these security checkpoint screening stations 12,14 and 16, and of scanning devices 18, will be described in more detailbelow with respect to FIGS. 2 and 3.

In the embodiment depicted, the security checkpoint screening system 10comprises a computer readable storage medium storing a centralizedrepository 22. The centralized repository 22 receives and stores theX-ray images generated by the scanning devices 18. The centralizedrepository 22 may receive the X-ray images in substantially real-time,as the images are being generated by the security checkpoint screeningstations 12, 14 and 16. In order to be able to identify each of thereceived images at the centralized repository 22, each image file may beassociated with an identification stamp (which could be a serial number,for example), a time-stamp and an indication of which one of thesecurity checkpoint screening stations 12, 14 and 16 generated the X-rayimage.

As will be discussed further on in the description, the centralizedrepository 22 is in communication with the security checkpoint screeningstations 12, 14 and 16 over a computer network. The centralizedrepository 22 may be in wire-line or wireless communication with thesecurity checkpoint screening stations 12, 14 and 16. Any suitablesecurity measures (encryption etc. . . . ) for protecting theinformation that is being transferred over the computer network may beused. Such security measures are well-known in the art and are beyondthe scope of the present application and as such will not be describedfurther here.

In certain circumstances, the centralized repository 22 may also receiveand store picture images, which may be video or still-shot images,obtained from the cameras 20. The picture images may also be associatedwith respective identification stamps (which could be serial numbers), atime-stamp and an indication of which of the security checkpointscreening stations 12, 14 and 16 generated the picture image. Thepicture image is mapped to an associated X-ray image in the centralizedrepository 22. This mapping may be done in any suitable manners known topeople of skill in the art.

As shown in FIG. 1, the centralized repository 22 is in communicationwith a monitoring module 24 and a screening module 26. The monitoringmodule 24 includes one or more processing units programmed to performvarious functions including process monitoring, system monitoring andprocess optimization. A purpose of the monitoring module 24 is togenerate and maintain information on the security screening process thatcan be used to performed diagnostics and/or an analysis of how theprocess is performing. Such information may be used, for example, toidentify potential issues/problems in the process and/or indentify areasthat require improvement. In a non-limiting example of implementation,the monitoring module 24 computes/collects threat detection statistics,maintains a log of automated detection results, maintain a log ofcertain X-ray images in the centralized repository 22 and/or perform anyother useful processes. The operations performed by the monitoringmodule 24 are beyond the scope of the present application and as suchwill not be described in further detail here.

It is also to be appreciated that, although useful in practice, themonitoring module 24 may be omitted from certain alternativeimplementations of the invention.

During operation, the centralized repository 22 passes the imagesreceived from the security checkpoint screening stations 12, 14 and 16to the screening module 26. In accordance with the embodiment of theinvention depicted in the figures, the screening module 26 comprises anautomated thread detector (ATD) module 28 for processing the images todetect potential threats depicted in the images. The automated threaddetector (ATD) module 28 also includes functionality to highlight (orotherwise direct the attention of a human operator towards) regions ofinterest (ROIs) in the images potentially depicting a threat or aprohibited object. In an alternative embodiment, ATD-relatedfunctionality resides locally in the scanning devices 18, or on anothdevice separate from screening module 26, and the images stored in thecentralized repository 22 are associated with results obtained byapplying ATD operations. In such alternative embodiment, the ATD 28 canbe omitted from the screening module 26.

In accordance with a specific example of implementation, the screeningmodule 26 also comprises a dispatch module 30 programmed for:

dispatching the images, when appropriate, to one or more remotescreening stations 32 associated with human operators. The remotescreening stations 32 are generally provided with a display screen (orportable viewing device) on which the X-ray images (which may includethe results of the ATD process) can be viewed. The display screens ofthe remote screening stations 32 may display multiple X-ray imagesconcurrently. The remote screening stations 32 may also be configured tosupport multiple different languages, such as English, French, German,Italian, Chinese, Dutch, etc. For example, at a remote screening station32, a human operator can select a preferred language at the time oflogon, or at the time of setting up a user account.

Transmitting threat assessment information associated with the images,when appropriate, to one or more on-site screening techniciansassociated with the scanning devices 18. The threat assessmentinformation may convey that a given object depicted in an image ismarked for further inspection or and that object is marked as clear.

It should be appreciated that the remote screening stations 32 may belocated within relative physical proximity to the security checkpointscreening stations 12, 14 and 16 (for example in a same room), oralternatively may be located in a different room, different wing,different building or different city, among other possibilities.

In a specific example of implementation, threat assessment informationassociated with the objects under inspection is transmitted to theon-site screening technicians regardless of whether an item underinspection has been marked as “clear” or marked for further inspection.Alternatively, threat assessment information is transmitted to theon-site screening technicians only when items under inspection have beenmarked for further inspection. For the purpose of completeness, thepresent description will consider the case where threat assessmentinformation is transmitted to the on-site screening techniciansregardless of whether an item under inspection has been marked as“clear” or marked for further inspection.

In the case where the screening module 26 and/or a human operator at oneof the remote screening stations 32 determines, on the basis of an X-rayimage, that the item under inspection is unlikely to contain a threat,threat assessment information conveying that the piece of luggage ismarked as “clear” is transmitted to one or more of the on-site screeningtechnicians located in proximity to the scanning devices 18. Inaccordance with a non-limiting example, threat assessment informationmay be sent to a receiver device at the scanning device 18, such as tocause a display screen 150 at the scanning device 18 to display amessage to the associated on-site screening technician conveying thatthe piece of luggage is marked as clear. The message may take on manyforms. For example, the message may be a very simple, rudimentarymessage, such as:

the illumination of a green-light when the object exits the scanner;

a text message, such as “clear”, “OK”.

Optionally, the image message may include the scanned (X-ray) image ofthe item as well as a picture image, video or still-shot, of the item astaken by one of the cameras 20.

In the case where the screening module 26 and/or a human operator at oneof the remote screening stations 32 determines, on the basis of an X-rayimage, that there could be a potential threat within an item underinspection, threat assessment information conveying that the piece ofluggage is marked for further inspection is transmitted to one or moreof the on-site screening technicians located in proximity to thescanning devices 18. The threat assessment information may betransmitted to the screening technicians in a variety of differentmanners. In accordance with a first non-limiting example, threatassessment information may be sent to a receiver device at the scanningdevice 18, such that a display screen 150 at the scanning device 18 iscaused to display a message to the associated on-site screeningtechnicians conveying that the piece of luggage is marked for furtherinspection. The message may take on many forms. For example, the messagemay be a very simple, rudimentary message, such as:

the illumination of a red-light when the object exits the scanner;

a text message, such as “hold and search”, “inspect this bag” or “thisobject may contain a threat”.

Alternatively, the message may be more sophisticated, and provide theon-site screening technician with an indication of the potential threat,such as:

a text message that indicates the type of threat that has been detected,such as “this item may contain a gun” or “this item may containflammable liquid”;

an image message that shows the item under inspection and points to, orotherwise visually identifies, the area of the item that should befurther inspected. Optionally, the image message may include the scannedimage of the item as well as a picture image, video or still-shot, ofthe item as taken by one of the cameras 20.

In the case where the threat assessment information conveys that theitem is marked to undergo further (manual or other) inspection, theon-site screening technician at the security checkpoint screeningstation may stop the conveyor belt 106 of the screening apparatus whilethe further inspection is taking place, such that further images are notsent to the centralized repository 22. Alternatively, when an item isrequired to undergo further inspection, it is dispatched to another(secondary) screening area where it is further inspected such that thescreening of items by the inspections devices 18 is uninterrupted.

In accordance with an alternative non-limiting embodiment, the threatassessment information may be sent to a wireless portable device held byone or more of the on-site screening technicians. In such a case, theon-site screening technicians may each have a dedicated portable devicethat is able to receive wirelessly from the screening module 26 threatassessment information associated with items screened by theirrespective security screening station 12, 14 or 16. When the threatassessment information conveys that an item has been marked for furtherinspection, the message displayed on the wireless portable device may,for example, take on any of the forms described above.

A display screen on the wireless portable device may further display agraphical user interface (GUI) that is able to convey messages to theon-site screening technician and provide functionality for permittinginteractions with the on-site screening technician.

The above examples are presented here for the purpose of illustrationonly, and are not intended to limit the scope of the invention. It willbe appreciated by the person skilled in the art, in light of the presentdescription, that the message conveying that the piece of luggage ismarked for further inspection, or is marked as clear, may take on avariety of different forms without departing from the spirit of theinvention.

The manner in which the screening module 26 handles the X-ray imagesthat are received from the security checkpoint screening stations 12, 14and 16 can be done in a variety of manners, which will be discussed inmore detail further on in the description, under the heading“centralized image screening”.

By having the images from a plurality of security checkpoint screeningstations 12, 14 and 16 pooled at a centralized location, certaininefficiencies that were associated with operating the securitycheckpoint screening stations 12, 14 and 16 in “stand-alone mode” can bereduced.

Firstly, such a system 10 can be helpful in reducing the delays due tothe displacement of the various items under inspection through thescreening stations 12, 14 and 16. For instance, as will be appreciated,when using conventional X-ray scanning devices of the type used insecurity screening, there is a delay time between the time a piece ofluggage (or other item under inspection) is placed on the conveyor beltof the X-ray scanning device and the time an X-ray image associated withthe item under inspection is generated and displayed for viewing by ascreening operator. There may also be empty space on the conveyor beltbetween two different items under inspection which also results infurther delays and a reduction in efficiency.

Further delays are incurred when the operator at a conventional scanningdevice moves the conveyor belt forwards or backwards (or stops the belt)to displace the items under inspection between different areas of theX-ray scanning device 18 in order to examine in greater detail the imageof the items under inspection. In systems making use of automated threatdetection (ATD) processes/systems, it is also to be appreciated thatthere is a delay time between the time the X-ray image associated withthe item is generated and the time the ATD results are obtained andprovided to the screening operators.

By pooling the images obtained from multiple scanning devices, some ofthese time delays can be curtailed. In a specific example ofimplementation, the images dispatched to a remote screening station 32would only be dispatched for viewing by a human operator once thecomplete image has been collected at one of the screening stations 12,14 or 16 (eliminating the lag time associated with displacing the itemon the conveyor belt through the screening area). Optionally, the imagesdispatched to a remote screening station 32 would only be dispatched forviewing by a human operator once the complete image has been collectedand the results applying an ATD operation to the image, either by theautomated threat detection ATD module 28 or by a local ATD moduleassociated with a scanning device 18. In this fashion delays associatedwith the scrolling of the image as well as delays associated withapplying ATD operations to the image can be accounted for and result amore efficient usage of human operator time. Moreover, since images frommultiple screening stations (12, 14 and 16 in the present embodiment)are pooled together, the overall throughput of the visual inspection ofthe images is less likely to be affected by delays associated toscreening at a particular screening station. For example, even if one ofthe multiple screening stations is stopped, the processing of imagesoriginating from the other screening stations by human operators atremote screening stations 32 can go on, thereby also resulting in a moreefficient usage of the human operators' time.

The above can impact both the time taken to screen items, and the numberof employees required to man each of the security checkpoint screeningstations 12, 14 and 16. Depending on how the centralized system isimplemented, it is believed that efficiency improvements ranging betweentwenty (20%) and thirty (30%) percent or higher over stand-alone X-raymachines could be obtained. In some cases this would result in improvedthroughput of the security checkpoint (with the associated improvementin traveler's satisfaction) and/or in a potential reduction in thenumber of people required to man the security checkpoints (with theassociated reduction in costs) while still achieving similar throughputlevels.

Security Checkpoint Screening Stations 12, 14, 16

Shown in FIG. 2 is a checkpoint screening station 100 suitable forobtaining an X-ray image (or alternative other type of image obtainedusing penetrating radiation) in accordance with a specific example ofimplementation of the present invention. Checkpoint screening station100 corresponds to any one of screening stations 12, 14 16.

As depicted, the checkpoint screening station 100 includes a scanningdevice 18 for scanning objects, a processing module 112 and acommunication device 150 for conveying information to an on-sitescreening technician.

The scanning device 18 is adapted for scanning an item, such as a pieceof luggage or a liquid product for example, that may contain a potentialthreat (which could be a weapon, an explosive, or an unauthorizedliquid, among other possibilities) using X-rays to generate X-ray dataconveying an X-ray image of the item under inspection. In a specificexample of implementation, the scanning device 18 is in the form of anX-ray machine typical of the type of device used to scan pieces ofluggage at security checkpoints within airports and other transportationlocations. The X-ray machine may be a single view X-ray machine or amulti-view X-ray machine.

The processing module 112 receives the X-ray data from the scanningdevice 18 and transmits that

X-ray data to the centralized repository 26 over a network connection(not shown). In a specific example of implementation, the processingmodule 112 includes the required hardware and software components forenabling a bi-directional communication between the scanning device 18and other devices on the network including the central repository 22. Ina variant, the processing module 112 is programmed to apply ATDoperations to the X-ray images and to transmit the results of the ATDoperations to the centralized repository 22 along with the associatedX-ray images.

The communication device 150 may be any device suitable for conveyinginformation to a user of the checkpoint screening station 100. In theembodiment depicted, the communication device 150 is in the form of alocal display device that displays message to an on-site screeningtechnician based on threat assessment information associated with theX-ray images generated. In a non-limiting implementation (not shown inthe figure) the local display device is positioned near the exit of thetunnel of the X-ray scanning device 18. It is to be appreciated thatalthough the embodiment depicted in FIG. 2 shows a communication device150 in the form of a display screen, it is to be appreciated thatcommunication device 150 may take other forms, such as for example aportable device (including a smart-phone for example) that can becarried by the on-site screening technician or a computing stationseparate from scanning device 18. In addition, although communicationdevice 150 is shown as displaying an image, it will be apparent to theperson skilled in the art in light of the present description that othersuitable forms of communication can be used. In other specific examplesof implementation, the communication device 150 may include a printeradapted for displaying in printed format information related to thedetermined threat status of the item under inspection. As a variant ofthis non-limiting example, the printer is configured to print threatstatus information on a label type substrate. The printed threat statusinformation may be in the form of a barcode, for example. In such casesthe on-site screening technician takes the label and affixes it to theitem under inspection using the adhesive on the backside of the label.The person skilled in the art will readily appreciate, in light of thepresent specification, that other suitable types of communicationdevices may be used in alternative examples of implementation of thepresent invention.

The scanning device 18 will now be described in greater detail withreference to FIG. 3. As depicted, the scanning device 18 includes ascanning area 104, a conveyor belt 106, an X-ray source 108 and an arrayof X-ray detectors 110. The scanning device 18 performs an X-rayinspection by subjecting items in the scanning area to penetratingradiation in the form of X-rays to generate X-ray image data.

The scanning area 104 (also referred to as scanning tunnel) is definedby an enclosed void between the X-ray source 108 and the array of X-raydetectors 110. The scanning area 104 is typically horizontally orientedand is dimensioned both vertically and horizontally to accommodate thetypes of items to be scanned, including pieces of hand-carried luggageallowed onboard a commercial aircraft, such as handbags, backpacks,briefcases and shopping bags, among others as well as liquid productsincluding bottles holding liquids and electronic devices, such ascameras and lap-top computers. The scanning area 104 is centrallytraversed by a conveyor belt 106 that is used to displace items to bescanned both into and out of the scanning area 104.

The items to be scanned can be placed either directly on the conveyorbelt 106 or in one or more trays that are then placed on the conveyorbelt 106.

The conveyor belt 106 is a horizontally-oriented continuous belt ofmaterial arranged in an endless loop between two terminal rollers. Thebelt 106 has an exterior surface on which objects or trays containingthe items to be scanned are placed, as well as an interior surfacewithin which the terminal rollers (as well as other guide rollers and/orsupports) lie.

The width of the conveyor belt 106 is sufficient to accommodate theplacement of trays within which the items to be scanned (e.g. liquidproducts, wallets, and lap-top computers) are placed, while its overalllength is sufficient to create an endless loop whose length includes:

A pre-scan area that lies before the scanning area 104, where the itemsto be scanned are placed on the belt 106;

The scanning area 104, where the items being scanned are subjected topenetrating radiation (i.e. X-rays); and

A post-scan area that lies after the scanning area 104, where the itemsthat have been scanned emerge after being subjected to penetratingradiation. It is in that area that a user can pick up his or her items(such as luggage items, lap-top computers and liquid products amongstothers) and/or where items under inspection that have been marked forfurther inspection are forwarded for dispatch to secondary screening.

It is worth noting that the terminal rollers constituting the end pointsof the conveyor belt 106 at the pre-scan and post-scan areas may beconnected to motors (not shown) that allow an operator to move the belt106 forwards or backwards to displace the objects to be scanned betweendifferent areas of the X-ray scanning device 18.

The X-ray source 108 is the source of penetrating radiation (in thiscase, X-ray radiation). The X-ray source 108 is located opposite to thearray of X-ray detectors 110 so that X-rays emitted by the source 108pass through the items under inspection that are located on the conveyorbelt 106 and are detected by the array of X-ray detectors 110 as aresult. In a non-limiting example, the scanning device 18 is adual-energy X-ray scanner and the X-ray source 108 emits X-rays at twodistinct photon energy levels, either simultaneously or in sequence.Example energy levels include 50 keV (50 thousand electron-volts) and150 keV, although persons skilled in the art will appreciate that otherenergy levels are possible.

The array of X-ray detectors 110 detects the penetrating radiation (i.e.X-rays) that was emitted by the X-ray source 108 and that penetrated theitems under inspection. The array of X-ray detectors 110 is locatedopposite to the X-ray source 108 so that X-rays that are emitted by thesource 108 pass through the items that are located on the conveyor belt106 and are detected by the array 110.

Centralized Image Screening

With reference to FIG. 1, the X-ray images are generated by the multiplesecurity checkpoint screening stations 12, 14 and 16 are transmitted tothe centralized repository 22 over a network connection. Optionallyresults obtained by applying ATD operations to the images at thecheckpoint screening stations 12, 14 and 16 are also transmitted to thecentralized repository 22 over the network connection.

These X-ray images (and optional ATD results) are stored in a computerreadable storage device and form part of the centralized repository 22.

In a non-limiting example of implementation, the X-ray images in thecentralized repository 22 are passed to the screening module 26 in afirst-in-first-out (FIFO) manner.

In an alternative example of implementation, the images may beassociated with respective priority rankings either depending on thesecurity checkpoint screening stations 12, 14 and 16 used (for examplethere may be a station for higher priority flights/people) or dependingon some other type of criteria. In this alternative implementation, theimages in the centralized repository 22 may be provided to the screeningmodule 26 out of order depending on their priority ranking so thatimages associated with a higher priority are provided before imagesassociated with lower priority. Variants in the scheduling of the imagescan also be contemplated—for example images may be associated to apriority ranking that is modified in accordance with how long the imagehas been waiting (using an image time-stamp for example). Such variantswill become readily apparent to the person skilled in the art in lightof the present description and as such will not be described in furtherdetail here.

The screening module 26 (shown in FIG. 1) is in communication with thecentralized repository 22 for receiving X-ray images associated withitems under inspection by the scanning devices 18 at the differentsecurity checkpoint screening stations 12, 14, 16. Optionally, ATDresults (when available) associated with the X-ray images are alsotransmitted to the screening module 26 over the network connection.

As will be described in more detail below, the screening module 26comprises a processor, a memory unit for storing data and programinstructions for use by the processor and an output in communicationwith one or more remote screening stations 32. The screening module 26is also in communication with the (local) communication devices 150associated with each of the security checkpoint screening stations 12,14, 16 either directly or through the processing module 112 (shown inFIG. 2) for conveying the threat assessment information to on-sitescreening technicians at the security checkpoint screening stations 12,14, 16.

As mentioned above, the manner in which the screening module 26processes the received images can be done in a variety of differentmanners, some non-limiting examples of which are described below.

EXAMPLE 1

All images are transmitted to a remote screening station

Shown in FIG. 5 is a first non-limiting example of a process that can beused by the screening module 26 in order to process the X-ray imagesreceived from the centralized repository 22. In this first example, allthe images that are received from the centralized repository 22 areprovided to a remote screening station 32, such that it is a humanoperator that determines whether or not the items should be marked as“clear” (e.g. allowed to be claimed by the owner without additionalinspection) or marked for further inspection (e.g. caused to undergomanual inspection by an on-site screening technician at the securitycheckpoint screening station).

At step 502, the screening module 26 receives an X-ray image, or a setof images, from the centralized repository 22. The images may bereceived at the screening module 26 one-at-a-time, or in sets, amongother possibilities. For the purpose of this example, the images areprovided to the screening module 26 in a first-in-first-out (FIFO)manner, such that the images are received at the screening module 26 inan order that is consistent with the order that the images are receivedat the centralized repository 22. In the specific embodiment, shown, itis the dispatch module 30 (shown in FIG. 1) that receives the images.

At step 504, an automated threat detection (ATD) operation is caused tobe performed on the received X-ray images. More specifically, the imagesare passed to ATD module 28 that is programmed for detecting a potentialthreat (such as a weapon, an explosive or an unauthorized liquid) withinthe image, and in certain circumstances for causing a portion of theimage that contains a detected potential threat to behighlighted/emphasized as being a region of interest (ROI). Performingan ATD operation on an image may be useful in providing assistance to ahuman operator associated with a remote screening station 32 inassessing the threat status of an item under inspection. The ATDoperation may be performed using any suitable process known in the art.The specific ATD operations applied are being the scope of the presentapplication and as such will not be described in further detail here.

It is to be appreciated that in alternative implementations in which theATD operations are applied locally at the security checkpoint screeningstations by processing module 112 (shown in FIG. 2), the ATD resultsassociated with the X-ray images are already available through thecentral repository 22 and thus step 504 can be omitted.

Once the ATD results for an X-ray image are obtained, at step 506, theX-ray image along with the ATD results are processed by the dispatchmodule 30, which forwards the ATD processed image (X-ray image +ATDresults) to the next available remote screening station 32. Theavailability of a given remote screening stations 32 may be determinedautomatically by the dispatch module 30 or/alternatively may be inferredfollowing the receipt of a request signal issued by a human operator atthe screening station 32. In a non-limiting implementation, the requestsignal is triggered by the human operator by pressing a key or buttonindicating that the human operator is ready to receive the next imagefor visual inspection. In response to receipt of a request signal, thescreening module 26 transmits the image for display and visualinspection to the remote screening station 32 that issued the requestsignal. The image displayed at the remote screening station 32 mayinclude the X-ray image generated by the scanning device 18 (shown inFIG. 1) as well as additional information made available by the ATDoperation. In the case where the ATD operation detected a potentialthreat within the image, the ATD processed image that is provided to theremote screening stations 32 may include one or more visual cues (suchas a highlighted portion) identifying a region of the image in which apotential threat may be located. This information is intended to assistthe human screener associated with screening station 32 in focusing onan area of interest when visually inspecting the ATD processed image tomore easily indentify potential threats.

In certain circumstances, a picture image (which may be a video orstill-image) from the camera 20 (shown in FIG. 1) may be provided to theremote screening stations 32 together with the ATD processed image, suchthat the human operator associated with the remote screening station 32is provided with some visual context surrounding the scanned item thathe/she is inspecting in addition to the X-ray image of the item. Thepicture image from the camera 20 may be provided to the remote screeningstation 32 with every ATD processed image or with only those images inwhich a potential threat has been detected by applying the ATDoperations. Alternatively, the picture image may only be provided to theremote screening stations 32 when explicitly requested by the humanoperator. In such a case, the screening module 26 will only provide thepicture image to the remote screening stations 32 “on-demand”.

In the embodiment shown in FIG. 1, two (2) remote screening stations 32are shown. It should however be appreciated that, in alternativeexamples of implementation of the invention, there could be a singleremote screening station or more than two (2) remote screening stations32. In cases where there are two (2) or more remote screening stations32, the dispatch module 26 of the screening module 26 may distribute theATD processed images to the plurality of remote screening stations 32 ina variety of manners. For example:

in accordance with a pre-determined order, such the ATD processed imagesare distributed in an orderly fashion, wherein the remote screeningstations 32 receive the ATD processed images in sequence in a pollingmode (one at a time);

on-demand, such that whenever a remote screening station 32 issues arequest for another image (via pressing a button, or clicking on an iconon a GUI, for example) that remote screening station 32 is provided withthe next ATD processed image;

on the basis of the security checkpoint screening station that generatedthe image, wherein different human operators are responsible fordifferent scanning devices 18. In this manner, the dispatch module 30may be configured to forward images originating from the same two orthree scanning devices 18 to a same remote screening station 32;

on the basis of experience. For example, the dispatch module 30 may beconfigured to forward an ATD processed image with a detected potentialthreat to one of the screening stations 32 associated with a humanoperator having more experience. Alternatively, a same image may be sentto two or more remote screening stations 32 in parallel to get multiplethreat assessments. This is particularly useful in situations where atrainee (having less experience) is reviewing the X-ray images at thesame time as his supervisor (having more experience). The trainee could“practice” visually inspecting real X-ray images while the results ofthe visual inspection obtained by the supervisor would be the ones used.This configuration has the advantage of not impacting throughput (atleast not significantly) nor screening quality;

on the basis of the type of threat, wherein the dispatch module 30 maybe configured to forward images depending on a type of potential threatdetected (i.e. weapon, explosive, liquid, etc) to a specific one of thescreening stations 32.

It is to be appreciated that the above examples are given for thepurposes of illustration only, and that other variants will becomeapparent to the person skilled in the art in light of the presentdescription.

As a result of the visual inspection of the ATD processed image, thehuman operator at the remote screening stations 32 can assign a threatlevel indicator to the X-ray image. The threat level indicator mayconvey that the item is marked for further inspection or that the itemis marked as clear. In a specific example of implementation the remotescreening stations 32 provide a user control interface for allowing theuser operator to enter the threat level indicator. The user controlinterface may be, for example, in the form on a key pad, one or moreicons on a GIU operable via a touch sensitive screen or any othersuitable means for enabling a human operator to provide the threat levelindicator in association with an X-ray image. Optionally, the remotescreening station 32 may provide a user interface tool for allowing thehuman operator to draw on or otherwise annotate the displayed X-rayimage in order to depict (or refine) the Region of Interests (ROIs) inthe image or provide some additional information.

The threat level indicator provided by the human operator, along withthe (annotated) X-ray image and optionally a picture image of the itemunder inspection, are then transmitted over the network to an on-sitescreening technician located at the appropriate security checkpointscreening station. The threat assessment information may be transmittedto a communication device 150 (described above with reference to FIG. 2)associated with one of the screening technicians. The threat assessmentinformation may contain any of the messages as described above, amongstothers instructing the screening technicians to perform further manualinspection of the item under inspection is appropriate.

EXAMPLE 2

only images for which the ATD results conveyed no detected threats arereviewed by a human operatorfor other images (i.e. those for which the ATD results conveyed thepresence of a potential threat) visual inspection by a human operator isby-passed and threat assessment information conveying that the items ismarked for further inspection is automatically generated by thescreening module 26 based on the ATD results

Shown in FIG. 6 is a second non-limiting example of a process that canbe used by the screening module 26 in order to process the X-ray imagesreceived from the centralized repository 22. In this second example,when an ATD operation detects a potential threat within an image, thescreening module 26 automatically generates and transmits threatassessment information to the corresponding security checkpointscreening station conveying that the item has been marked for furtherinspection. In this manner, the step of displaying such images at thescreening station 32 for visual inspection by a human operator isby-passed. The other ATD processed images (i.e. the images for which theATD did not detect any potential threat) are provided to a remotescreening station 32, such that a human operator can perform a visualinspection of the X-ray image.

In a first variant, when an ATD operation detects within an image aliquid product, the screening module 26 automatically generates andissues threat assessment information to the corresponding securitycheckpoint screening station conveying that the item has been marked forfurther inspection. In this fashion, the step of displaying images atthe screening station 32 conveying liquid containers is by-passed.

In another but similar variant, when an ATD operation detects within animage a liquid product holding a liquid constituting a potential threat,the screening module 26 automatically generates and issues threatassessment information to the corresponding security checkpointscreening station conveying that the item has been marked for furtherinspection. In this fashion, the step of displaying images at thescreening station 32 conveying liquid containers where the liquid in thecontainer was determined to constitute a potential threat is by-passed.

It is to be appreciated that a human operator observing an X-ray imageof a container of liquid will not be able to make a determination as tothe nature of the liquid in the container. As such, by by-passing thescreening station 32 in cases where the liquid held in a container is athreat, an improvement in efficiency can be achieved without having animpact on the overall security screening performance. The other ATDprocessed images (the images for which the ATD did not detect liquidcontainers holding potential liquid threats) are provided to a screeningstation 32, such that a human operator can determine whether anypotential threats were missed by the ATD operation performed by ATDmodule 28.

Steps 602 and 604 are similar to steps 502 and 504 as described abovewith reference to FIG. 5. At step 602, the screening module 26 receivesan image, or a set of images, from the centralized repository 22, and atstep 604, an automated threat detection (ATD) operation is performed onthe received images. Similarly to step 504, step 604 may be omitted forimplementations in which the ATD operations are applied locally at thesecurity checkpoint screening stations by processing module 112 (shownin FIG. 2).

At step 606 the screening module 26 determines, on the basis of theresults obtained by applying an ATD operation to an X-ray image, whethera potential threat has been detected within that X-ray image.Determining whether a potential threat has been detected may be done ina variety of manners and will generally be based on pre-defined criteriaand heuristic rules, such as:

whenever a liquid product is detected, it may be determined that apotential threat has been detected or, alternatively, whenever a liquidproduct determined to contain a potential threat is detected, it may bedetermined that a potential threat has been detected;

whenever a pre-defined confidence level has been exceeded as to thepresence of a threat, it may be determined that a potential threat hasbeen detected;

whenever a certain shape has been detected (such as a gun shape), it maybe determined that a potential threat has been detected.

When at step 606 the screening module 26 determines based on the ATDresults that a threat has been detected, the system proceeds to step608, where the screening module 26 generates and a transmits threatassessment information, along with the X-ray image and optionally apicture image of the item under inspection, to an on-site screeningtechnician located at (or in proximity to) the security checkpointscreening station that generated the X-ray image. A visual cueidentifying the region of the image where the potential threat wasidentified may also be transmitted. The threat assessment informationconveys to the on-site screening technician that the item underinspection has been marked for further inspection.

As described above, upon determination that the image depicts apotential threat, threat assessment information is generated by thescreening module 26. Optionally, one of the human operators at one ofthe remote screening stations 32 can be advised of this determinationprior to the threat assessment information being transmitted to theon-site screening technician located at (or in proximity to) thesecurity checkpoint screening station that generated the X-ray image,such that this human operator is given the opportunity to override thedecision made by the screening module 26. In this manner, a humanoperator has the ultimate decision to submit or override threatassessment information that will be sent to the on-site screeningtechnicians at the security checkpoint screening station. Alternatively,the threat assessment information that is generated by the screeningmodule 26 is transmitted to the security checkpoint screening stationdirectly without having been reviewed by a human operator. In thismanner, the visual inspection by the human operator at remote screeningstation 32 is by-passed.

In the case where the screening module 26 did not determine, on thebasis of the ATD processed image and the pre-defined criteria, that apotential threat was detected, the screening module 26 proceeds to step610 which forwards the ATD processed image (X-ray image+ATD results) tothe next available remote screening station 32.

Step 610 of this process is similar to step 506 described above withreference to FIG. 5, and as such the description will not be repeated indetail herein. It should, however, be appreciated that the ATD processedimage that is provided to the remote human screener 32 may includevisual cues in order to identify a region of interest that did not meetthe pre-defined criteria for automatically being considered a potentialthreat, but that nevertheless may be useful in visually inspecting theimage.

Step 612 of this process is similar to step 508, described above, and assuch the description will not be repeated herein.

EXAMPLE 3

Only images identified by the ATD results and containing potentialthreats are reviewed by a human operator in order to assign threatassessment information.for other images (i.e. those for which the ATD result does not conveysthe presence of a potential threat) visual inspection by a humanoperator is by-passed and threat assessment information conveying thatthe items is marked as clear is automatically generated by the screeningmodule 26 based on the ATD results

Shown in FIG. 7 is a third non-limiting example of a process that can beused by the screening module 26 in order to process the X-ray imagesreceived from the centralized repository 22. In this third example,images that contain a potential threat, as identified by resultsobtained by applying an ATD operation, are provided to a human operatorassociated with one of the remote screening stations 32 for visualinspection in order to determine whether or not the object associatedwith the image should be marked as “clear” (i.e. no additionalinspection required) or marked for further inspection. The other ATDprocessed images for which no threat have been identified by the ATDoperation are not further visually inspected by a human operator. Thevisual inspection is thus by-passed for these images. As a side note, itis to be appreciated that this alternative embodiment places a highlevel of reliance on the abilities of the ATD engine to detect thepresence of threats. In practical implementations, the rate of falserejections (threats being detected by the ATD engine when there is infact no threat in the image) would likely have to be set to a higherlevel in order to be able to rely more comfortably such a system.

Steps 702 and 704 are similar to steps 502 and 504 as described abovewith reference to FIG. 5 and as such the description of these steps willnot be repeated here.

At step 706 the screening module 26 determines, on the basis of resultsobtained by applying an ATD operation to an X-ray image, whether apotential threat has been detected within that X-ray image. Determiningwhether a potential threat has been detected on the basis of the ATDprocessed image may be done in a variety of manners and will generallybe based on pre-defined criteria, such as:

whenever a liquid product is detected, it may be determined that apotential threat has been detected or, alternatively, whenever a liquidproduct determined to contain a potential threat is detected, it may bedetermined that a potential threat has been detected;

whenever a pre-defined confidence level in the detection of a threat hasbeen exceeded, it may be determined that a potential threat has beendetected. In this example, the pre-defined confidence level may be setquite low, such that a wide net is cast, and a potential threat isdetected whenever an image displays any questionable region of interest;

whenever a certain shape has been detected (such as a gun shape), it maybe determined that a potential threat has been detected.

When the screening module 26 determines based on the ATD results that animage does not contain any potential threat, the screening module 26proceeds to step 708, where the screening module 26 generates and atransmits threat assessment information, along with the X-ray image andoptionally a picture image of the item under inspection, to an on-sitescreening technician located at (or in proximity to) the securitycheckpoint screening station that generated the X-ray image. The threatassessment information conveys to the on-site screening technician thatthe item under inspection has been marked as clear and can be releasedto its owner. In this manner, X-ray image that have been determinedunlikely to contain a potential threat with a high level of comfortby-pass visual inspection by a human operator at a remote screeningstation 32.

However, when the screening module 26 determines at step 706 that an ATDprocessed image potentially contains a threat, the screening module 26proceeds to step 710 which forwards the ATD processed image (X-ray image+ATD results) to the next available remote screening station 32.

Step 710 of this process is similar to step 506 described above withreference to FIG. 5, and as such the description will not be repeated indetail herein.

Step 712, which follows step 710, is similar to step 508, as describedabove, and as such the description will not be repeated here.

EXAMPLE 4

treat images differently depending on threat type

Shown in FIG. 8 is a fourth non-limiting example of a process that canbe used by the screening module 26 in order to process the X-ray imagesreceived from the centralized repository 22. In this fourth example,images are assigned to one or more different categories based on resultsobtained by applying an ATD operation to the images and the images arehandled differently depending on their assigned category. This allowsfor a screening process that takes into consideration different threattypes, and treats different threat types differently.

Steps 802 and 804 are substantially the same as steps 502 and 504 asdescribed above in with reference to FIG. 5 and as such the descriptionwill not be repeated here.

At step 806 the screening module 26 assigns to categories the ATDprocessed images. In general, the different categories relate todifferent threat types that can be detected by the ATD operations. Forexample, each ATD processed image may be assigned to a categoryaccording to whether:

a liquid product (e.g. a bottle holding a liquid) has been detected;

a weapon has been detected;

an explosive has been detected;

an un-identified threat has been detected;

no threat has been detected;

multiple threats have been detected;

a lap-top has been detected;

a complicated image has been detected;

etc. . . .

Once an image has been assigned a category, the image is then furtherhandled at least in part on the basis of its category.

For example, in the case where an image has been categorized ascontaining a liquid product, that image may then be considered by afurther liquid detection process at step 808 ₁, in order to detect thetype of liquid that is depicted within the image and/or whether theliquid detected should be considered as a threat. Some suitableprocesses for determining whether a liquid product constitutes a threatare described, for example, in:

International application PCT/CA2007/001658 filed on Sep. 17, 2007;

International application PCT/CA2009/000811 filed Jun. 9, 2009;

International application PCT/CA2009/000395 filed Mar. 27, 2009; and

International application PCT/CA2009/000401 filed on Mar. 27, 2009.

The contents of the aforementioned documents are incorporated herein byreference.

Once the assessment as to whether the liquid product constitutes athreat has been determined, the image, together with information(textual, audio or other) indicating whether the liquid product wasfound to constitute a potential threat, may be passed to a one of thescreening stations 32 for viewing by an associated human operator. Thehuman operator can then make the determination as to whether the itemassociated with the image should be marked as “clear” (i.e. no furtherinspection required) or marked for further inspection (e.g. furthermanual inspection required). Threat assessment information may betransmitted to a communication device 150 (described above withreference to FIG. 2) associated with one of the screening technicians atthe security checkpoint screening station that generated the X-rayimage.

In an alternative example, when an image has been categorized aspotentially containing a weapon, the image will be handled in adifferent manner at step 808 ₂. For example, the ATD processed image(X-ray image+ATD results) may be forwarded to the next available remotescreening station 32 for visual inspection, for example to a humanoperator specializing in weapons detection. Optionally, the image may besubjected to a materials analysis process at step 808 ₂ prior to beingdisplayed for visual inspection at a remote screening station 32, inorder to determine whether the image displays any objects that are of amaterial that is commonly used in weapons.

In yet a further alternative example, an image may be categorized ascontaining multiple potential threats (for example, both a liquidproduct and an explosive may be detected). In the case where multiplepotential threats are detected within an image, the screening module 26may cause the image to be handled in yet a different manner. Forexample, the screening module 26 may cause the image to undergo a seriesof different steps in order to be able to consider all of the detectedthreats in a systematic manner. In the case where both a liquid productand an explosive threat are detected by the ATD operation, the screeningmodule 26 may first cause the image to undergo a liquid detectionprocess in order to identify the liquid and/or determine whether theliquid in question is a threat. In the case where the liquid has beendetermined as unlikely to constitute a threat, the screening module 26may then cause the image to be displayed for visual inspection at aremote screening station 32 associated with a human operatorspecializing in explosives. However, in the case where the liquidproduct is determined as likely to constitute a threat, the screeningmodule 26 may then cause the image to be concurrently (or sequentially)displayed for visual inspection at a screening station 32 associatedwith a human operator specializing in liquids, and at a remote screeningstation 32 associated with a human operator specializing explosives.

It should be appreciated that in the case where multiple potentialthreats are detected, the screening module 26 may handle the imagedifferently depending on:

the types of the potential threats detected;

the number of potential threats detected;

a severity ranking of the different potential threats detected withinthe image;

the training of the human operators currently on duty;

the additional processing operations that are available (i.e. materialsdetection processing, liquid identification processing, etc. . . . )

These different criteria may be taken into consideration in programlogic and instructions that are used by the screening module 26 toprocess the images being considered.

In yet a further embodiment, in the case where multiple potentialthreats are detected, the screening module 26 may by-pass visualinspection of the image and automatically cause threat assessmentinformation conveying that the item has be marked for further inspectionto be transmitted to one or more on-site screening technicians locatednearby the security checkpoint screening station that generated theimage.

General Process

FIG. 13 shows a generalized example of a process that can be used toprocess the X-ray images originating from one of more of the securitycheckpoint screening stations 12, 14 and 16. It is to be appreciatedthat the processed described with reference to FIG. 13 may be used insituations where images are pooled from multiple security checkpointscreening stations and are visually inspected remotely from the securitycheckpoint screening stations or, alternatively, in situations whereimages originated from a single security checkpoint screening stationand are visually inspected either locally or remotely from the securitycheckpoint screening station.

At step 1302, which is similar to steps 502 described above withreference to FIG. 5, X-ray images derived by scanning the pieces ofluggage with X-rays are received.

At step 1304, which is similar to steps 504 described above withreference to FIG. 5, the X-ray images are processed with an automatedthreat detection engine.

At step 1306, a determination is made as to whether to subjectrespective ones of the X-ray images to a visual inspection by a humanoperator at least in part based on results obtained by the automatedthreat detection engine. Various criteria may be used to make thisdetermination, for example but limited to, the criteria described withreference to FIGS. 6, 7 and 8 described above.

If at step 1306 it is determined that an X-ray image is to be subjectedto a visual inspection, the system proceeds to steps 1308 and 1310.Steps 1308 and 1310 are similar to steps 506 and 508 described withreference to FIG. 5. For the purpose of conciseness the description ofthese steps will not be repeated here.

If step 1306 it is determined that an X-ray image is not to be subjectedto a visual inspection, visual inspection the X-ray image is by-passedand the system proceeds to step 1312 where the X-ray image is assigned athreat level indicator based on results obtained by the automated threatdetection engine. For example, if the automated threat detection enginedetected a threat, then the assigned threat level indicator would conveythat the X-ray image has been marked for further inspection. Converselyif the automated threat detection engine has determined that the X-rayimage conveyed safe contents, then the assigned threat level indicatorwould convey that the X-ray image has been marked as clear.

The threat level indicators provided at step 1312 or 1310, along withthe X-ray image and optionally a picture image of the item underinspection, are transmitted over the network to an on-site screeningtechnician located at the appropriate security checkpoint screeningstation that generated the image.

Screening Station—Variant

FIG. 12 is a block diagram of a screening station 1200 in accordancewith a variant of the invention. The configuration of screening station1200 may be used in connection with any one of or all screening stations12, 14 and 16 shown in FIG. 1.

In the figure, the screening station 1200 includes an X-ray scanningdevice 1214, a workstation 1216 and post-scan areas 1206 1208. The X-rayscanning device 1214 (which is analogous to scanning device 18) includesa conveyor belt and a scanning area, the conveyor belt carrying piecesof luggage into and out of the scanning areas where the pieces ofluggage are exposed to X-rays in order to generated X-ray images of thepieces of luggage. In the specific example depicted, the conveyor beltis extended in order to provide what is in effect a conveyor system inwhich additional sections of conveyor 1204 have been added, inparticular in the post-scan areas 1206 and 1208, in order to control thedisplacements of the piece of luggage post-scan.

In a non-limiting example of implementation, the workstation 1216renders an X-ray image of a piece of luggage for visual inspection by ahuman operator. In such implementation, the workstation 1216 provides auser interface tool enabling the human operator to assign threat levelindicators to displayed X-ray images. The workstation 1216 mayoptionally implement ATD operations to assist in the threat detectionprocess and wherein the ATD operations may also contribute to assigningthreat level indicators to X-ray images. Optionally, the visualinspection of X-ray images is performed at least in part at a remotescreening station (not shown in FIG. 12) and threat level indicators aresent to the workstation 1216 where they are conveyed to the humanoperator at workstation 1216.

The screening station 1200 depicted also includes a mechanical device1212 to separate pieces of luggage (or other objects) at the entrance ofthe X-ray tunnel; a divider wall 1202 to isolate a portion of the X-rayconveyor from the passengers area 1222, such as to prevent passengersfrom accessing pieces of luggage until they are marked as clear; and aswitching area 1210 to direct pieces of luggage to different post-scanareas 1206 1208 of the screening station 1200. In the example depictedthere are two (2) post-scan areas namely a luggage collection area 1206and an area for dispatch to secondary screening 1208. In the luggagecollection area 1206, pieces of luggage marked as clear can be collectedby the passengers while in the area for dispatch to secondary screening1208 pieces of luggage are subjected to further examination, includingfor example a manual search. It is to be appreciated that alternativeimplementations of screening stations may include additional post-scanareas without detracting from the spirit of the invention.

In a non-limiting example of implementation, the threat level indicators(which were either entered by the human operator at workstation 1216,which were provide by applying an ATD operation or which were providedby a remote screening station) are used to control a displacement of thepieces of luggage after scanning by the X-ray scanning device 1214.

In a first exemplary implementation, the control of the displacement ofthe pieces of luggage is exercised manually by an on-site securitytechnician in the switching area 1210. In such implementation, theinformation which is displayed on workstation 1216 conveys to theon-site security technician that a piece of luggage should be directedto either to the luggage collection area 1206 (when the threat levelindicator conveys that the piece of luggage is marked as clear) or tothe area for dispatch to secondary screening 1208 (the threat levelindicator conveys that the piece of luggage is marked for furtherinspection). The on-site security technician relies on this informationto place the corresponding piece of luggage so that it is displacedtowards the proper post-scan area.

Alternatively, in a second exemplary implementation, the control of thedisplacement of the pieces of luggage is exercised electronically. Insuch alternative implementation, switching area 1210 includes a controldevice (which may be part of workstation 1216 or which may be a separatecomponent) programmed to control, based on the threat level indicators,a mechanical switch in the conveyor system for directing the pieces ofluggage either to the luggage collection area 1206 (when the threatlevel indicator conveys that the piece of luggage is marked as clear) orto the area for dispatch to secondary screening 1208 (the threat levelindicator conveys that the piece of luggage is marked for furtherinspection). The control device relies on threat level indicators tocontrol the position of the mechanical switch so that the correspondingpieces of luggage are displaced towards the proper post-scan area. Thespecific construction of the conveyor system and associated mechanicalswitch used for directing the flow of the pieces of luggage is notcritical to the invention and as such will not be described in furtherdetail here.

Specific Practical Implementation

Certain portions of the screening system 10 depicted in FIG. 1, such asfor example screening module 26, may be implemented on a general purposedigital computer. FIG. 9 of the drawings shows a simplifiedrepresentation of a general purpose digital computer 900 on which thescreening module 26 may be implemented and which includes a processingunit 902 and a memory 904 connected by a communication bus. The memory904 stores data 908 and program instructions 906.

The processing unit 902 is adapted to process the data 908 and theprogram instructions 906 in order to implement the functions describedin the specification and depicted in the drawings. The digital computer1300 may also comprise an I/O interface 910 for receiving or sendingdata elements to external devices, such as the for receiving informationfrom the centralized repository 22 and transmitting information to oneor more remote screening stations 32 and for transmitting threat levelindicators to the on-site screening technicians associated with thecheckpoint screening stations 18 (all shown in FIG. 1).

Alternatively, the above-described screening module 26 can beimplemented on a dedicated hardware platform where electrical/opticalcomponents implement the functions described in the specification anddepicted in the drawings. Specific implementations may be realized usingICs, ASICs, DSPs, FPGA or other suitable hardware platform.

Other alternative implementations of the screening module 26 can beimplemented as a combination of dedicated hardware and software, of thetype depicted in FIG. 10 and generally designated by reference numeral1000. Such an implementation comprises a dedicated image processinghardware module 1008 (which could form part of the ATD 28) and a generalpurpose computing unit 1006 including a CPU 1012 and a memory 1014connected by a communication bus. The memory 1014 stores data 1018 andprogram instructions 1016. The CPU 1012 is adapted to process the data1018 and the program instructions 1016 in order to implement thefunctions described in the specification and depicted in the drawings.As depicted, this specific implementation also comprise one or more I/Ointerfaces 1004 1002 for receiving or sending data elements to externaldevices such as for receiving information from the centralizedrepository 22 and for transmitting information to one or more remotescreening stations 32 and for transmitting threat assessment informationto on-site screening technicians associated with the security checkpointscreening stations 18 (all shown in FIG. 1).

It will be noted that the security screening system 10 depicted in FIG.1 is of a distributed nature where the X-ray images are obtained by ascanning device 18 at one of the security screening stations 12, 14, 16and transmitted over a network to the centralized repository 22 and thescreening module 26 described above. The screening module 26 in turntransmits threat assessment information to one or more display devices150 or portable hand-held devices associated with on-site screeningtechnicians to display information, such as a message indicating that agiven item should be subjected to further manual inspection. Such amessage may include an X-ray image of a piece of luggage underinspection. The display device 150 may be located in the same locationwhere the X-ray images of items under inspection were obtained or in analternate location.

FIG. 11 illustrates a non-limiting network-based system 1500 forscreening items in accordance with a specific example of implementationof the invention. The system 1500 includes a plurality of computingdevices 1502, 1504 and 1506 (which could be the display devices 150and/or the handheld portable devices held by the on-site screeningtechnicians and/or the remote screening stations 32), scanning devices18 a 18 b and 18 c (which are each associated with a respective securitycheckpoint screening station 12, 14, 16) connected through network 1512to a computer system 1510. The communication links 1514 between thecomputing devices 1502, 1504, 1506, the inspections devices 18 a 18 band 18 c and the computer system 1510 can be metallic conductors,optical fibers or wireless, without departing from the spirit of theinvention. The network 1512 may be any suitable network including butnot limited to a global public network such as the Internet, a privatenetwork and a wireless network. In accordance with a non-limitingexample, the network is a dedicated 1 Gb/s network. The computer system1510 is adapted to process information received from the inspectionsdevices 18 a 18 b and 18 c and issue signals conveying image results tothe human screeners 32 at one or more of the computing devices 1502,1504, 1506 and issue threat assessment information to other ones of thecomputing devices using suitable methods known in the computer relatedarts.

The computer system 1510 includes a program element 1516 for executionby a CPU (not shown). In a non-limiting example, the program element1516 includes functionality to implement the functionality of screeningmodule 26 and optionally the functionality of the monitoring module 24described above. The computer system 1510 may also include a computerreadable storage medium (not shown) for storing the centralizedrepository 22.

Program element 1516 also includes the necessary networkingfunctionality to allow the computer system 1510 to communicate with thecomputing devices 1502, 1504, 1506, 1508 and scanning devices 18 overnetwork 1512. In a specific implementation, the computing devices 1502,1504, 1506 include display devices responsive to signals received fromthe server system 1510 for displaying screening results derived by theserver system 1510.

Although the above embodiments have been described with reference to ascanning device 18 (shows in FIG. 1) embodied in a single view X-rayimaging apparatus, it is to be appreciated that embodiments of theinvention may be used in connection with any suitable type of inspectiondevice including multi-view X-ray imaging apparatus, as well as thecameras 20.

It will therefore be appreciated that other various modifications willbecome apparent to those skilled in the art and are within the scope ofthis invention, which is defined more particularly by the attachedclaims.

1-53. (canceled)
 54. A method for screening items at a security checkpoint, the security checkpoint including a pre-scan area and at least two post-scan areas, said method comprising: a) receiving image data derived by scanning the items using penetrating radiation, the image data conveying images of the items; b) assigning threat level indicators to respective items being screened at the security checkpoint at least in part by processing any one of: i) automated threat detection results and human-provided threat assessment information associated with images conveyed by the image data; ii) automated threat detection results associated with images conveyed by the image data absent any human-provided threat assessment information; and iii) human-provided threat assessment information associated with images conveyed by the image data; c) processing the threat level indicators assigned to the items associated with the images conveyed by the image data to electronically control switches in a conveyor system to control a displacement of the items through the security checkpoint thereby directing respective ones of the items to a selected one of the at least two post-scan areas.
 55. A method as defined in claim 54, wherein one or more scanning devices are used to derive the image data by scanning the items using penetrating radiation.
 56. A method as defined in claim 55, wherein the human-provided threat assessment information is received from a human operator associated with a remote screening station, the remote screening station being located remotely from at least one of the one or more scanning devices used to derive the image data.
 57. A method as defined in claim 56, wherein the one or more scanning devices include at least two scanning devices.
 58. A method as defined in claim 56, wherein the assigning of the threat level indicators to respective items being screened at the security checkpoint is performed at least in part by processing one of: i) the automated threat detection results and the human-provided threat assessment information associated with images conveyed by the image data; and ii) the automated threat detection results associated with images conveyed by the image data absent any human-provided threat assessment information.
 59. A method as defined in claim 58, said method comprising processing at least some images conveyed by the image data with an automated threat detection engine to derive the automated threat detection results.
 60. A method as defined in claim 59, said method further comprising displaying at least some of the images conveyed by the image data on a displayed device at the remote screening station associated with the human operator so that visual inspection of the at least some of the images may be performed for the at least some images.
 61. A method as defined in claim 60, wherein the images displayed for visual inspection at the remote screening station convey to the human operator information derived at least in part based on the automated threat detection results obtained by processing the image data with the automated threat detection engine.
 62. A method as defined in claim 61, wherein said method comprises processing the derived automated threat detection results to: a) identify at least some images conveyed by the image data as images to be subjected to visual inspection by the human operator at the remote screening station; and b) identify at least some other images conveyed by the image data as candidates for by-passing visual inspection by the human operator at the remote screening station.
 63. A method as defined in claim 62, wherein assigning threat level indicators to respective items includes assigning specific threat level indicators to at least some items associated with a subset of images amongst the images identified as candidates for by-passing visual inspection, the specific threat level indicators being assigned at least in part by processing automated threat detection results associated with the subset of images absent any threat assessment information from the human operator at the remote screening station.
 64. A method as defined in claim 62, wherein at least one of the images is identified as a candidate image for by-passing visual inspection when the information derived by the automated threat detection engine conveys an indication of safe contents in connection with the at least one of the images.
 65. A method as defined in claim 56, said method comprising displaying information derived at least in part based on the threat level indicators on display devices associated with on-site screening technicians located in proximity to the one or more scanning devices.
 66. A method as defined in claim 56, wherein one of the at least two post-scan areas is a luggage collection area and another one of the at least two post-scan areas is an area for dispatch to secondary screening.
 67. A method as defined in claim 54, wherein at least some threat level indicators convey that associated items are marked for further inspection.
 68. A method as defined in claim 54, wherein at least some threat level indicators convey that associated items are marked as clear.
 69. A method as defined in claim 66, wherein the items being screened at the security checkpoint include pieces of luggage.
 70. A method as defined in claim 55, wherein at least one of the one or more scanning devices is an X-ray device and wherein the image data includes X-ray image data.
 71. A system for screening items at a security checkpoint, the security checkpoint including a pre-scan area and at least two post-scan areas, said system comprising: a) one or more scanning devices for scanning the items with penetrating radiation to derive image data, the image data conveying images of the items; b) a threat level determination processor in communication with the one or more scanning devices for receiving the image data, the threat level determination processor being programmed with software for: i) receiving the image data derived by scanning the items with the at least one scanning device; ii) assigning threat level indicators to respective items being screened at the security checkpoint at least in part by processing any one of: (1) automated threat detection results and human-provided threat assessment information associated with images conveyed by the image data; (2) automated threat detection results associated with images conveyed by the image data absent any human-provided threat assessment information; and (3) human-provided threat assessment information associated with images conveyed by the image data; iii) a conveyor system controller in communication with said threat level determination processor, said conveyor system controller including at least one processor programmed for processing the threat level indicators assigned to the items associated with the images to electronically control switches in a conveyor system to control a displacement of the items through the security checkpoint thereby directing respective ones of the items to a selected one of the at least two post-scan areas.
 72. A system as defined in claim 71, wherein the human-provided threat assessment information is received from a human operator associated with a remote screening station, the remote screening station being located remotely from at least one of the one or more scanning devices used to derive the image data.
 73. A system as defined in claim 72, wherein the one or more scanning devices include at least two scanning devices.
 74. A system as defined in claim 71, wherein said system further comprises local display devices associated with respective ones of said least two scanning devices in communication with the threat level determination processor, said local display devices conveying information derived at least in part based on the threat level indicators associated with the items being screened to on-site screening technicians located in proximity to at least one of the one or more scanning devices.
 75. A system as defined in claim 72, wherein the assigning of the threat level indicators to respective items being screened at the security checkpoint is performed at least in part by processing one of: i) the automated threat detection results and the human-provided threat assessment information associated with images conveyed by the image data; and ii) the automated threat detection results associated with images conveyed by the image data absent any human-provided threat assessment information.
 76. A system as defined in claim 75, said threat level determination processor includes an automated threat detection engine configured for processing at least some images conveyed by the image data to derive the automated threat detection results.
 77. A system as defined in claim 76, wherein said threat level determination processor is programmed for processing the automated threat detection results to: a) identify at least some images conveyed by the image data as images to be subjected to visual inspection by the human operator at the remote screening station; and b) identify at least some other images conveyed by the image data as candidates for by-passing visual inspection by the human operator at the remote screening station.
 78. A system as defined in claim 77, wherein assigning threat level indicators to respective items includes assigning specific threat level indicators to at least some items associated with a subset of images amongst the images identified as candidates for by-passing visual inspection, the specific threat level indicators being assigned at least in part by processing automated threat detection results associated with the subset of images absent any threat assessment information from the human operator at the remote screening station.
 79. A system as defined in claim 78, wherein at least one of the images is identified as a candidate image for by-passing visual inspection when the information derived by the threat detection engine conveys an indication of safe contents in the at least one of the images.
 80. A system as defined in claim 72, wherein one of the at least two post-scan areas is a luggage collection area and another one of the at least two post-scan areas is an area for dispatch to secondary screening.
 81. A system as defined in claim 75, wherein at least some threat level indicators convey that associated items are marked for further inspection.
 82. A system as defined in claim 75, wherein at least some threat level indicators convey that associated items are marked as clear.
 83. A system as defined in claim 71, wherein the items being screened at the security checkpoint include pieces of luggage.
 84. A system as defined in claim 72, wherein at least one of the one or more scanning devices is an X-ray device and wherein the image data includes X-ray image data.
 85. A system as defined in claim 77, wherein the one or more scanning devices include at least two scanning devices and wherein said threat level determination processor programmed for: i) identifying which one of the at least two scanning devices generated a specific candidate image amongst the images identified as candidates for by-passing visual inspection; ii) by-passing visual inspection at the remote screening station of the specific candidate image; and iii) causing threat assessment information based on automated threat detection results derived by processing the specific candidate image with the automated threat detection engine to be transmitted to a computing device associated with an on-site screening technician located in proximity to the scanning device that generated the specific candidate image.
 86. A computer program product including computer executable instructions tangibly stored on one or more tangible computer readable storage media, said instructions when executed, causing a programmable system including at least one programmable processor to implement operations for screening items at a security checkpoint, the security checkpoint including a pre-scan area and at least two post-scan areas, said operations comprising: a) receiving image data derived by scanning the items using penetrating radiation, the image data conveying images of the items; b) assigning threat level indicators to respective items being screened at the security checkpoint at least in part by processing any one of: i) automated threat detection results and human-provided threat assessment information associated with images conveyed by the image data; ii) automated threat detection results associated with images conveyed by the image data absent any human-provided threat assessment information; and iii) human-provided threat assessment information associated with images conveyed by the image data; c) processing the threat level indicators assigned to the items associated with the images to generating control signals to electronically control switches in a conveyor system to control a displacement of the items through the security checkpoint thereby directing respective ones of the items to a selected one of the at least two post-scan areas; d) releasing the control signals. 